I strongly recommend against Waterfox, Pale Moon, and Iceraven.
https://divestos.org/index.php?page=browsers
Edit:
To elaborate why:
- Iceraven is consistently 1-2 releases behind Fenix
- Waterfox was recently purchased by an advertising company
- Pale Moon is both hostile to the open source community and based off an extremely old version of Firefox and they undoubtedly do not have the security team that Mozilla has to maintain it to any proper manner.